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Contact Lens Guides
Contact Lens Prescription vs Glasses Prescription: Why They Are Different
A contact lens prescription is not simply a spectacle prescription copied onto a different product.
Why the Power Can Differ
Contact lenses sit directly on the eye, while spectacle lenses sit at a distance in front of it. For some prescriptions, this affects the required power.
Contact Lenses Need Additional Parameters
Base curve, diameter, brand or material and, where relevant, cylinder, axis and add power may be part of the fitting.
Fit Is Part of the Prescription
A lens that provides the right power but fits poorly may still be unsuitable.
Do Not Self-Convert
Use a professional contact lens assessment rather than assuming an online conversion is sufficient.
Laxmi Opticians education note: These guides are designed to help you understand the terminology before you buy. Final recommendations should consider your prescription, fitting, visual needs and professional advice.
Frequently Asked Questions
Can I buy contacts using only my glasses prescription?
A separate contact lens fitting is generally needed to determine appropriate lens parameters.
Why is my contact lens power different?
Lens position and fitting considerations can lead to different values, particularly at stronger powers.
